PROJECT SUMMARY We often consider our movements a result of sensory processing ? sensation guides behavior. However, animals selectively shape future sensory input through their own actions in a process known as active sampling. Thus, action and sensation are inextricably linked. Despite this, much of the research done on sensory processing restricts movement, most commonly via head fixation. To access sensorimotor processing during more natural behavior, we will study olfactory navigation in freely-moving mice. The olfactory system is ideal for studying sensory sampling, because of its ethological relevance for mammalian foraging and the dynamic nature of airborne odor stimuli. The proposed research will determine the sampling strategies of olfactory search and reveal the underlying circuitry that connects sensation with motion. Aim 1. It is unknown how rodents navigate dynamic plumes of odorant towards an odor source. In this aim, we will identify, analyze, and model active sensing behaviors that occur during increasingly difficult navigation tasks and with single nostrils occluded. These experiments will test the hypothesis that olfactory navigation works as a sensorimotor closed-loop system, where animals optimize sampling behaviors for the current stimulus conditions. These behavioral studies will lay the foundation for investigations of sensorimotor processing in dynamic olfactory scenes. Aim 2. To determine how sampling movements shape sensation, we will monitor neural activity during active sensory behavior. During odor tracking, we will electrophysiologically record in the olfactory bulb, a bottleneck through which all sensory input passes. We will determine the sensory history dependence of active sampling and, in doing so, reveal part of the underlying circuitry that connects motion with sensation. These experiments will test the hypothesis that sampling movements are sensory history dependent. To our knowledge, sampling movements and sensory activity have never been simultaneously recorded during olfactory navigation. This research will advance our understanding of the interplay between sensation and motion during natural behavior.